Liquid cooler



March 30,1937.

D. H. DOLISON LIQUID COOLER Filed April 50, 1954 lNV ENTOR ATTORNEY Patented Mar. 30, 1937 attain mourn ooornn Dewey H. Dolison, Mount Vernon, Ohio, assignor to The Brunswick-Balke-Collender Company, Chicago, Ill., a corporation of Delaware Application April 30, 1934, Serial No. 723,121

13 Claims.

This invention relates to refrigerating systems and more particularly concerns an improved refrigerating system of the type used to cool liquids,'su ch as drinking water and other beverages,

which are subject to continuous or intermittent draft from an uncooled source.

Known devices for cooling liquids, such as drinking water, beer, carbonated water for fountain use and other beverages, which are subject to continuous or intermittent draft, have customarily employed a flooded type of evaporator. In such flooded evaporator systems, a coil carrying the fluid to be cooled is immersed in liquid refrigerant, the refrigerant liquid level being kept substantially constant by a float valve or equivalent means. Flooded cooler systems of the type described, although satisfactory in certain respects, are expensive, require the use of a comparatively large quantity of refrigerant and cause operating difficulties due to the collection of oil or other lubricant in the evaporator chamber. The oil or other lubricant, which is employed to lubricate the compressor of the refrigcrating system, is delivered to the evaporator with the liquefied refrigerant and, depending upon its nature, this oil either stratifies above or below the refrigerant liquid or dissolves in the refrigerant. In any case, the collection of large quantities of oil in the evaporator disturbs the pressure-temperature relationship of the evaporator and causes undesirable frothing therein as the liquid refrigerant boils and gasifies. Further, it is difficult to effect the return of the oil from the evaporator to the compressor without at the same time removing some liquid refrigerant and thereby wasting refrigerating effect. If the oil is not returned to the compressor, all of the oil in the system eventually accumulates in the evaporator and the compressor is not lubricated.

With the above and other considerations in mind, it is proposed in accordance with the present invention to provide an improved cooling system for liquids or fluids subject to draft, which system avoids the disadvantages inherent in the flooded type systems above described. It is a further object of the invention to provide a system of this type incorporating improved control means for regulating the supply'of refrigerant to the evaporator in accordance with the draft requirements of the liquid being cooled. .The objects of the invention also include the provision of a draft cooling system which is economical to construct and operate, which employs a comparatively small quantity of refrigerant and which is very flexible in its range of operation.

through the suction line.

In carrying out the objects of my invention, I employ an evaporator chamber into which the liquid refrigerant is introduced in the form of a fine spray or mist. A coil or other duct carrying the liquid to be cooled is disposed within the 5 evaporator chamber and the vaporization or evaporation of the refrigerant mist within the chamber results in the absorption of heat from the liquid drawn throughythe coil, thereby providing the desired refrigerating efiect. No body 10 of liquid refrigerant is accumulated within the evaporator chamber, and the suction line for removing vaporized refrigerant from the evaporator is connected to the lower end of the chamber. With this arrangement, any lubricant de-- 15 livered to the evaporator with the refrigerant falls directly to the bottom of the chamber and is immediately returned to the compressor The direct passage of the lubricant through the evaporator does not 20 appreciably affect the evaporating action, since' no frothing can occur and no appreciable quantity of lubricant can collect in the chamber." Further, since no oil is trapped in the evaporator, the compressor is not robbed of oil and is properly 25 lubricated at all times. 1

I prefer to maintain the desired evaporator temperature, and thus the desired temperature of the liquid to be cooled, by suitable means which maintains a constant pressure in the evaporator 30 chamber. This evaporator pressure regulating means may comprise a valve in the suction line, operated by the pressure in this line. With this arrangement, the temperature of the evaporator is controlled by the pressure therein, which pres- 5 sure is an index of the evaporator temperature. The operation of the refrigerant compressor is also preferably controlled in accordance with the suction line pressure.

A draft cooler of the type here concerned is 40 necessarily subject to widely varying cooling loads and widely varying periods during which no drafts of liquid through the cooler take place.

It is accordingly desirable that the cooler be very flexible in operation and that the amount of re- 45 frigerating effect be accurately controlled in accordance with the variable refrigerating load imposed by liquid drafts of varying duration. For economy of operation, only sufficient refrigerant mist should be supplied to the evaporator to han- 50 die the particular cooling load imposed, since any excess of refrigerant supplied is withdrawn through the suction line unevaporated with a consequent loss of refrigerating effect.

In order to accurately control the supply of rer 2 a,ovs,1e4-

'this circuit and so stop the compressor when this I frlgerant to the evaporator in accordance with load conditions,'-I prefer to employ a refrigerant supply or expansion valve responsive to both the temperature of the draft liquid passing through the cooling coil and the temperature of the refrigerant supplied to the refrigerant spraying means in the evaporator chamber. This-may be accomplished by using a thermostatic bulb or like device for operating the refrigerant flow valve, and disposing this bulb in heat exchanging relation with both the liquid in the cooling coil and the refrigerant in the duct between the refrigerant control valve and the spray outlets in the evapo-' rator chamber. With this arrangement, the now '15 of refrigerant to the evaporator may be cut oil before the temperature of the liquid to be cooled has been reduced to the desired va1ue,'whereby the refrigerant mist remaining in the evaporator after the refrigerant supply valve is closed may be usefully employed in reducing the liquid tempera ture to the desired-low point. Further, the use of thermostatic means responsive to the refrigerant temperature ensures the rapid closing of the refrigerant supply valve, since the volatile liquid refrigerant absorbs heat very rapidly as it evaporates. This quick closing of the refrigerant supply or expansion valve is particularly advantageous when the draft of cooled liquid is of short durationand" the refrigerating effect required is correspondingly smalL. Various other advantages of my improved refrigerant flow control means will be pointed out or will become apparent as the descriptionof the invention progresses.

. The invention will be best understood by ref- I erence to the accompanying drawing in which:

Figure 1. is a diagrammatic elevation of a draft liquid cooling system embodying my invention, certain of the partsbeing shown in section to disclose the interior construction thereof;

Figure 2 is a plan view of the thermostatic bulb employed in the system of Figure. 1- for operating the refrigerant supply valve;

Figure 3 is a diagrammatic section of the device ofFigure2;and 1 r Figure 4 is a" sectional view of a modified form of thermostaticvalve operating bulb.

Referring tothe drawing, and more particularly to Figure 1, the system there disclosed as embodying my invention comprises generally a refrigerant o compressing and condensing unit C and an evaporator ,or low-side E. The refrigerant compressing and condensing unit may take any suitable known form, and .as shown, comprises a compressor 5 drivenby a motor 5 and connected to discharge compressed refrigerant into a condenser I. The-- intake 8 of the compressor; 5 is connected to the suction line 9 from the evaporator E, and the out-- let iii of the compressor is connected to' the inlet;

of the condenser I through the pipe IS. The outlet of the condenser 1 .is connected through a liq-' uid collecting chamber I i to the refrigerant supply line i2 leading back to the evaporator'E.

The compressor of the unit C preferably operates intermittently and may be automatically started and stoppedby any suitable control means pressure drops below a predetermined value. The switch S'may also be arranged to open the motor circuit if for any reasona dangerous or excessive pressure isbuilt up by the compressor and to this 5 end, a pressure connection is provided between .the compressor outlet Ill and the switch 8..

' 0 through which the liquid to be cooled passes.

The ends of the coil 0 pass through sealed open? 20 in'gs in the wall of the chamber i8, and the inlet end l8 thereof is connected to the source of liquid to be cooled, which may be a beverage reservoir or the mains of a drinking water supply system. The outlet end is of the coil 0 is pro- 25 vided with a tap or faucet "20 for controlling the draft of cooled liquid. The coil 0 shown in the disclosed embodiment comprises. a plurality of vertical sections 2i, 22, 23 .and 2| through each of which ,the liquid flows downwardly in the ordergiven. I A hollow central core 2! is secured to and depends from the top of the evaporator chamber l6 andpasses through the center of the inner-most 'coil section 24. The-core 2! is open at its lower end and acts to confine the refriger- 35 ant mist to the portion of the evaporator'chamber occupied by the coil 0 and to provide a space into which the evaporated refrigerant may expand after performing itsrefrigerating function. The refrigerant is sprayed over the coil 0 from L any suitable means such as the spray ring-20 disposed about the core 2i adJacent the upper end of the evaporator chamber IO. The 'sprayring 26 is provided with a plurality of downwardly disposed spray orifices through which the re- 45 frigerant passes in the form of a wet vapor or mist. The suction line 9 is connected to the J lower end of theevaporator chamber II, as

shown. v 1

In accordance with my invention, I prefer to 5 control the supply of liquid refrigerant which is sprayed into the evaporator E in response to both v the temperature of the draft liquid in the coil 0- and the temperature ofthe liquid refrigerant supplied to the spraying means. In the disclosed 55 v spray ring 26 and to, the temperature of the draft liquid in the coil (I) v at a point intermediate its ends. The valve V may take any suitable form and is essentially so constructed that it is opened to permit the flow of liquid refrigerant when the pressure of a thermally responsive fluid exceeds a predetermined value and is closed to cut off the liquid refrigerant flow. when-the pressure of the fluid falls below a predetermined value.

The valve V shown in thedrawing has an inlet 43 connected to the refrigerantsupply pipe i2 and an outlet 44 connectedto the refrigerant pipe 45 which supplies refrigerant to th sprayring 28. A valve element 46 is arranged control the flowof refrigerant between these pipes and is air/mas suitably connected to be operated by an expansible bellows 41, the interior of which bellows is connected to a pressure pipe 30. With the cohstruction shown, an increase in the pressure in the pipe 30 moves the valve element 5 to the right and soincreases the valve opening whereas a decrease in this pressure moves the valve element to the left and, if the pressure is low enough, closes the valve.

The pressure pipe as of the valve V is connected to a thermostat bulb chamber disposed in heat exchanging relation with both the draft liquid in the coil 0 and the liquid refrigerant supplied through the valve V to the spray ring 26. The bulb chamber may take various forms, and in the disclosed embodiment, comprises a chamber 3! disposed concentrically about a short section of the coil 0. The liquid refrigerant flowing to the spray ring 26 is brought into heat exchanging relation with the bulb chamber 3! by means of a refrigerant chamber 32 disposed concentrically about the bulb chamber 3! and connected in the liquid refrigerant flow path between the valve V and the spray ring 2d. The bulb chamber 3| contains a suitable thermally responsive fluid capable of expanding and contracting in re-' sponse to increases and decreases in its temperature. I prefer to so arrange the liquid refrigerant chamber 32 that after the valve V is closed, a certain amount of liquid refrigerant will be trapped therein. This is accomplished in the.

disclosed embodiment by disposing the outlet pipe 33 leading from the chamber 32 to the spray ring 26 at the top of the chamber 32 as shown in Figures 1 and 2. The relative arrangement of the chambers 3i and 32 and the coil 0 is diegrammatically shown in Figure 3.

A modified arrangement of the refrigerant supply valve operating bulb is shown diagrammatically in Figure 4. In this modification, the thermostatic bulb 3! is disposed within the coil 0 in direct contact with the draft liquid to be cooled and the liquid refrigerant supplied to the spray means is conducted through a concentric chamber 32' surrounding the section of the coil within which the bulb 3! is disposed;

As stated above, I prefer to locatethe temperature responsive bulb of the valve V intermediate the ends of the draft liquid coil 0. With this arrangement, when the cooler is subjected to a draft of liquid, the-bulb is not heated until a predetermined quantity of cooled liquid has been withdrawn and the uncooled liquid entering the coil has advanced to the point in the coil where the bulb is located. This prevents the supply of liquid refrigerant to the evaporator in response to liquid drafts of very short duration, while acting to supply refrigerant if a considerable liquid draft occurs. I have found that the'most satisfactory results are obtained if the bulb is located at a point between the inlet end of the coil and the center thereof, preferably between one-third and one-half of the distance from the inlet to the outlet end of the coil. As shown in the drawing, the bulb chamber 3| is located in the last turn of the second section 22 of the coil 0, and is thus between one-third and one-half of the distance from the inlet to the outlet end of the coil. v I 7 Any suitable means may be employed to maintain a substantially constant temperature in the evaporator chamber. In the disclosed embodiment,'this is accomplished by means of a pressure regulating valve P located in the suction line 9.

The valve- P may be of any suitable construction capable of maintaining a substantially constant pressure in the evaporator E. As shown, the valve member 35 of the valve P is operated by a bellows 35 exposed on one side to the pressure in the evaporator E and on the other side to atmospheric pressure and the pressure of a'variably adjusted spring 36. The spring pressure may be varied by rotation of the threaded sleeve 31 which raises or lowers a spring abutting nut 38, held against rotation with the sleeve 31 by a rod as. A central threaded stem to is provided for closing the valve when the system is not in use, and the spring adjusting sleeve 3'5 is held against accidental movement by a lock nut ti. with the arrangement described, an increase in pressure in the evaporator chamber beyond a predetermined point compresses the bellows 35 against the spring 36 and so opens the valve 35 and permits the escape of sufiicient refrigerant gas to lower the evaporator pressure to the desired point.

of my improved draft cooler, the inlet end l8 In the operation of the disclosed embodiment of the coil 0 is connected to the water mains or any other source of liquid to be cooled and the refrigerant compressing and condensing unit C is started ,up. Liquid refrigerant is generated by the compressing and condensing unit C and is sprayed in a fine mist over the coil 0 in the evaporator chamber E, the valve V being open at this point due to the comparatively high temperature of the liquid in the coil 0. The refrigerant mist evaporates in the evaporator chamber and thus cools the liquid in the coil 0, and after the desired low evaporator temperature has been attained, the rate of evaporation decreases to a point where the valve P closes. As the liquid to be cooled in the coil 0 approaches a temperature close to but somewhat higher than the desired minimum temperature, the contraction of the changed in size, the partial closing of the valvev V results in a gradual reduction in the pressure on the liquid refrigerant within the chamber 32 of the refrigerant line between the valve and the spray orifices. Up to this point, there has been little or no evaporation of liquid refrigerant in the chamber 32 because of the high pressure on the refrigerant therein. As this pressure decreases, however, some of the refrigerant in the chamber 32 boils and evaporates, absorbing heat from the bulb chamber 3! and thereby causing the quick closing of the valve V which cuts off further refrigerant flow to the spray ring 26. The valve V is so adjusted that it closes at a point when'the amount of liquid refrigerant mist 'remining in the evaporator is just suflicient to lower the temperature of the liquid to be cooled to the desired minimum value. In thismanner, the flow of liquid refrigerant is cut off at such a point that no unevaporated refrigerant mist is returned from the evaporator to the compressor, and waste of refrigerating effect is thereby avoided.

With the desired low temperature attained and the pressure regulating valve P closed, the pressure in the suction line 9 isquickly reduced by the compressor 5 to a point where the pressurethe valve V closes, and this refrigerant evapcrates slowly while the system remains idle.

This evaporation keeps the bulb chamber 3| at a terminated in the manner described above.

low temperature and prevents the opening of the refrigerant supply valve V due tq slight temperature rises during periods when there is no draft of cooling liquid.

When any considerable'amount of cooled liquid is drawn through the coil 0, the uncooled liquid advancing through this coil-reaches and heats the valve chamber 3i, opening the valve. V and admitting liquidrefrigerant to the spray ring 26. The evaporation of this refrigerant momentarily increases the evaporator pressure, opens the pressure valve P and increases the pressure 'on the switch S inthe suction line, thereby closing this switch and starting'the compressor driving motor 6. The cooling cycle then proceeds and is By controlling the supply of refrigerant to. the evaporator in accordance with both the draft within said evaporator chamber, means for spraying liquid refrigerant from said condenser into liquid temperature and the temperature of the a refrigerant before it reaches the spray means, I have provided a control valve which closes very quickly and so cuts, ofi' the refrigerant and avoids waste even-when the cooling period required is of very short duration. Further, this the refrigerant valve before the desired minimum liquid temperature is attained, whereby the unevaporated refrigerant remaining within thev '4 the draft liquid temperature at this latter point may be appreciably above the desired minimum temperature and even above the temperature atwhich the refrigerant valve opens.

It should be understood that the cooling -system of the invention may be employed to cool any 45 desired liquid or gaseous fluid. Since systems of the type described are-customarily employed to cool drinking water or other beverages, the mee iiium cooled has been referred to in the specificatlon and claims as a liquid. However, the term a liquid to be cooled is used herein in a generic sense and includes air or other gaseous media as well as drinking water, beverages and other l -y f i 'Iclaimz- 1. In a draft liquid cooler, in combination, means for successively compressing and condensing a volatile refrigerant, a vertically extending evaporator chamber, means for conducting a liquid to be cooled in heat exchanging relation with the interior of said evaporator chamber, means for spraying liquid refrigerant fromlsaid condensing means into said evaporator chamber at 43a point adjacent its upper end and means for withdrawing evaporated refrigerant from the lower end of said evaporator chamber to said compressing means, whereby any lubricant in-- troduced to said'evaporator chamber with the refrigerant falls through said chamber and is" returned to said compressing means. v

2. In a draft liquid cooler, in combination, a mechanical refrigerant compressor, a condenser connected to receive compressed refrigerant from said compressor and acting to liquefy the same, a vertically extending evaporator chamber, a coil 76 for carrying a liquid'subiect to draft disposed dual temperature control permits the/closing of said coil within said evaporator chamber and .to-

said evaporator chamber in the form of a fine mist whereby said coil isv cooled by evaporation of the liquid refrigerant, and means for withdrawing the evaporated refrigerant from the,

lower end of said evaporator chamber to said compressor whereby any lubricant'expelled from 1 said compressorand introduced to said evapora-- tor chamber with the liquid refrigerantfalls through said evaporator chamber andis returned to said compressor.

3. In a draft liquid cooler, an evaporator chamber, means for conducting a liquid subject 'to draft in heat exchanging relation with the interior of said evaporator chamber, a source of lique- "fied refrigerant, means for spraying liquid refrigerantfrom said source into said evaporator chamber in the form'of a fine mist, and means responsive to the temperature of the draft liquid and to the temperature of the liquid refrigerant supplied to said spray means for controlling the supply of liquid refrigerant to said spray means.

. 4. In a draft liquid cooler, an evaporator cham-- ber, a coil'in said chamber for conducting a liquid subject to draft through and in heat exchanging relation with the interior of said chamber. a source of liquefied refrigerant, means for spraying liquid refrigerant from said source into said evaporator chamber in the form of a fine mist. and means for'maintaining' the temperature of said draftliquid substantially constant comprising means for maintaining asubstantially constantpressure in said evaporator chamber and means responsive to the temperature of the draft liquid in said coil and to the temperature of the liquid refrigerant .before it passes to said spray means for controlling the supply of liquid refrigerant to saidevaporator chamber.

5. In a draft liquid cooler, an evaporator chamber, a coil in said-chamber for conducting a liquid subject to draft through and in'heat exchanging f relation with the interior of said chamber, a

source of liquefied refrigerant, means for, spraying liquid refrigerant from said source into said evaporator chamber in the form of a fine mist,

and means responsive to the temperature of the draft liquid at a point intermediate the ends ofthe temperature of the liquid, refrigerant supplied to said spray means for controlling the supply of liquid refrigerant to said spray means. I

6. In a draft liquid cooler, an evaporator 'cham-' ber, a coil in said chamber for conductingga liquid subject to draft through and in heat exchanging relation with the interior. of- ,said chamber, a source of liquefied refrigerant, means for spraying liquid refrigerant from said source into said evaporator chamber in the form of a fine mist, and means responsive'to the temperature of the draft liquid at a point between the inlet end and the center of said draft liquidcoil for controlling the supply of liquid refrigerant to said spray means. I

7., In a draft liquid cooler, an evaporator cham subject to draft through and in heat exchanging ber, a coil-in said chamber for conducting a liquid relation with theinterior of said chamber, a

source of liquefied refrigerant, means for spraying liquid refrigerant from said. source'into said the center of. said draft liquid coil andto the ten perature of the liquid to sai 1o evaporator chamber in the form'of'aflne and means responsive to the temperature of .draft liquid at a point between the inlet end and.

, ao'raisa,

spray means for controlling the supply ofliquid refrigerant to said spray means.

8. In a draft liquid cooler, an evaporator cham ber, a coil in said chamber for conducting a liquid subject to draft in heat exchanging relation withthe interior of said chamber, a source of liquefled refrigerant, means for spraying refrigerant from said source into said evaporator chamber,

valve means for controlling the flow of liquid refrigerant from said source to said spray means,

- a bulb chamber carrying a thermally expansible fluid connected to operate said valve means, a refrigerant chamber in heat exchanging relation with said bulb chamber, means for conducting liquid refrigerant from said valve means to said refrigerant chamber and an outlet adjacent the upper end of said refrigerant chamber for conducting liquid refrigerant from said chamber-to said spray means whereby liquid refrigerant is trapped in said refrigerant chamber after the flow of liquid refrigerant to said refrigerant chamber is cut off by said valve mea'ns.

9. In a draft liquid cooler, an evaporator chamber, a coil in said chamber for conducting a liquid subject to draft in heat exchanging relation with the interior of said chamber, a source of liquefied refrigerant, means for spraying refrigerant from said source into said evaporator chamber, valve means for controlling the flow of liquid refrigerant from said source to said spray means, a bulb chamber disposed in heat exchangi'ng relation with said draft liquid coil and carryving a thermally expansible fluid connected to operate said valve means, a refrigerant chamber in heat exchanging relation with said bulb chamber, means for conducting'liquid refrigerant from said valve means to said refrigerant chamber and an outlet adjacent the upper end of said refrigerant chamber for conducting liquid refrigerant from said chamber tosaid spray means whereby liq-- uid refrigerant is trapped in said refrigerant chamber after the flow of liquid refrigerant to said refrigerant chamber is cut off by said valve means; 10. In a draft liquid cooler, an evaporato chamber, a coil in said chamber for conducting a' liquid subject to draft through and in heat exchanging relation with the interior of said chamber, a source of liquefiedrefrigerant, means for sprayingliquid refrigerant from said source into said evaporator chamber in the form of a fine mist, a valve for controlling the flow of liquid refrigerant from said source to said spray means and means for controlling said valve comprising a bulb chamber carrying a thermostatically expansible fluid and disposed in heat exchanging relation with a section of said coil, means for operating said valve .in accordance with the fluid pressure in said bulb chamber, a refrigerant chamber disposed in heat exchanging relation with said bulb chamber and means for conducting means.

the liquid refrigerant flowing from said valve to said spray means through said refrigerant chamber. 11. In a draft'liquid' changing relation with the interior of said chamber, a source of liquefied refrigerant, means for spraying liquid refrigerant from said source into said evaporator chamber in the form of a fine cooler, an evaporator chamber, a coil in said chamber for conducting a 1 liquid subject to draft through and in heat-exmist,'a valve for controlling the fiow of liquid r'e-' frigerant from said source to said spray means and means for controlling said valve comprising a bulb carrying a thermostatically expansible fluid and surrounding section of said coil, means for operating said valve in accordance with the fluid pressure in said bulb chamber, a refrigerant chamber surrounding said bulb chamber and means for conducting the liquid refrigerant from said valve to saidspray means through said refrigerant chamber.

- 12. In a draft liquid cooler, an evaporatorv chamber, a coil in said chamber for conducting a liquidsubject to draft through and, in heat exchanging relation with the interior of said chamber, a source of liquefied refrigerant, means for spraying liquid refrigerant from said'source into said evaporator chamber in the form of a fine mist, a valve for controlling the flow ofllquid refrigerant from said source to said spray means and means for controlling said valve comprising a bulb chamber carrying a thermostatically expansiblefluid and disposed within said coil, means for operating said valve in accordance with the fluid pressure in said bulb chamber, a refrigerant chamber disposed in heat exchanging relation with saidcoil adjacent the point where said bulb is disposed and means for conducting the liquid refrigerant flowing from said valve through v 40 T said refrigerant chamber and to said spray -13. In a draft liquid cooler, an evaporator chamber, a coil in said chamber for conducting a liquid subject to draft through and in heat exchanging relation with the interior of said chamber, a source of liquefied refrigerant, means for spraying liquid refrigerant from said source intosaid evaporator chamberin the form of a fine mist, a valve for controlling the flow of liquid refrigerant from said source tosaid spray means and means for controlling said valve comprising a bulb chamber carrying a thermostatically expansible fluid and disposed within said coil, means for operating said valve in accordance with the 

